Variable-displacement radial-piston pump



l/NVEA/To?. TONY M. MOULDEN BY H15 ATTORNEYS. Hamas/(15CH, FOSTER HARK/.s

Sept. 18, 1951 T. M. MOULDEN VARIABLE DISPLACEMENT RADAL PIs'roN PUMP .Filed Nov. 26, 1948 Patented Sept. 18, 1951 UNITED STATES Towne. Mouwen; Mnnosooalin ppli'cation ovemlxer 26, glff Serialu o. 2,625

M'y irwoniaion` reidteisin general torotry'piiidps 93nd, more pdrticularly, to' device of" te' type' having radiallymovable' pistons for pmnpm'g fluidi a" primary obj'ect of' trie invention being" tiorprvide a vajriabfe displacement pillnp of' rotor' to which nie' pistons are" obnrieoid" sind annular eccentrics in synchronism -from an inoperative position vihere'ix'rl they' drei-n opposition t'o" an operaitiviy position wherein they .firefiL ape position so* aisl tof shif't the auxiliary' rotor e.;

Anv important object of" the irvefntorij` fo provide a pump of` the foregoing' genel ch'a# acter liavi'ng means for shifting the -eLui'iliTy' rotorlaterally witlilrespect t0y the xffati'irotors?)a 92s to vdry'tlie stroke ofi the-pistons in'. the-irrel spect'ive cylinders, whereby t'oivar'y the dspl'c'ement of' the pump;

Another objectisto provide.suolil a pump hving means lfor shifting. the auxiliary rotor from" aninoperati'Vev position wherein the auxilry axis` coincides` with the exis of! rot'alti'on oftl'i'e m'laiin4 rotor" and wherein the displacement of te' pumpY is'zro to an operativepositon wherein tleauxilia'ryaxis is spac'edfi'orn the' axis of lrotation ofthe main rotor'Y and' wherein" the dispicient" of` the pump is greaterv than zero".I

A Another object is. to provide means" for shift'-V ing the auxiliary' rotor between inoperative' amd"` operativepositionsA in a plane'. v

Another` importanti object is to provide a" orn means for l shifting the auxilidryrotor wh'in comprises a, pair of sstn'nulitr"eece'ntris'disposedJ one within the' other.`

tion"v to an operativer position' wherein tliy ajieiiisv 2)* advantages s'uggegesteclAl thereby-,- together p Figi- 4 a-vie'w similarto4 Figi4 a aridi snowing l Y y 3 which is rotatable about an auxiliary axis B-B, the auxiliary rotor being shiftable laterally with respect tothe main rotor between an inoperative position, shown in Figs. 1 to 3 ofthe drawing, wherein the vauxiliary axis B-B coincides with the main axis A-A, and various operative positions, one of which is shown in Fig. 4 of the drawing, wherein the auxiliary axis is spaced from the main y axis. fThe device also includes cam means I8 for shifting the auxiliary rotor,` I1 be-1 tween its operative and inoperative positions, actuating means I9 for operating thecam means, and means 2U responsive to uid pressure in the outlet port I3 for operating the actuating means.;V f-

15" ing IIl is provided with inlet and'outlet bosses.- f,

Considering the device in more detail, the hous- 22 and 23 having bores 24 and 25 therethrough which respectively communicatezwith-the inlet and outlet ports I2 and I3, the respective bosses 22 and 23 being provided with counterbores 26 and 2 to receive inlet and outlet pipes (not shown), or the like. Connected to one end ofv the housing i by bolts 30 is a bracket 3| .byl means of which the device may be mounted on a suitable supporting structure, the bracket being` provided with holes 32 for mounting bolts (not shown), or the like. vThe oppositeend ofthe housing IU is provided with a recess 33 for the actuating means I9, a cover plate 34 for the recess 33 being connected to the housing by means of bolts 35.

Disposed within the chamber I I in the housing is an annular liner 38 which defines a rotor,

chamber 39, the liner having a plurality of apertures 4I] which provide uid communication between the rotor chamber and the inlet and outlet ports I2 and I3. The main'rotor. I4 is disposed in the rotor chamber39 and uincludes anf annular disci 4IA which encircles the auxiliary rotor I1, the cylinders I5 extending through the annulardisc in radial directions with re-l spect to the main axis A--A. The outer periphery of the annular disc 4I makes substan tially fluid-tight contact with the inner periphery of the liner 38, i. e., the peripheral wall of the rotor chamber 39 and the sides of the annular disc engage thrust rings 42. Any fluid leaking between the annular disc 4I and the liner 38 on the high pressure side of the pump flows to the low pressure side thereof through clearances provided between the sides of the annular disc and the side walls of the rotor chamber 39, as best shown in Fig. 2 of the drawing.

The main rotor I4 includes a main shaft'45` which is formed integrally with the main rotor in the particular construction illustrated and the, axis `of which coincides with the main axis A-A, the shaft 45 extending through bearings 46 which are disposed in a counterbore 41 in thehousing I and which are separated by a bearingl spacer 48. A shaft seal 49 for preventing leakage fromv the rotor chamber 39 along the shaft 45 encircles the shaft and is disposed in V a counterbore I) in the housing IIJ. The shaft 45v extends through a bore 5I in the housing ID and is provided with means 52 for connection to any suitable device (not shown) for driving the main vrotor I4, the means 52 comprising a socket formed in lthe outer end 'of the shaft in the particular con-V struction illustrated.

The auxiliary rotor I1 comprises a master rodv 55 which is carried by a shaft means comprising an auxiliary shaft 56, the latter being provided with thrust collars 51 respectively engaging op,

posite Asides of the master rod. Preferably, an;

annular bearing insert 58 is disposed between the master rod and the auxiliary shaft 56. Asbest shown in Figs. 3 and 4 of the drawing, the master rod is pivotally connected to one of the pistons I6, and the remaining pistons are pivotally connected to the master rod by the link rods 59. l

Y As best shown in Figs. 1 and 2 of the drawing, the I, auxiliary shaft V56, `thefaxis of which coincides with the auxiliary axis B-B, is carried by a bearing B2 which is retained on the auxiliary shaft between one of the thrust collars 51 andva lwaswher 63 by a nut 64.

i; Consideringthefoperation of the pump as thus far described, it will be apparent that rotation of tl 1 e main `shaft 45 will result lin rotation of the main and auxiliary rotors I4 and I1, rotation of'fthe main motor being communicated to the auxiliary rotor through the pistons I6 and the connections between the pistons and the auxiliary rotor. As long as'the auxiliary rotor is in its inoperative position, i. e the position shown inFigs. 1 to 3 of the drawing, wherein the aux' iliaryvaxisv B-B coincides with the main axis A" A," theV pistons I6 remain stationary in the cylindersv I5 so that no fluid is displaced from the inlet port .I2 to the outlet port I3. In otherl the auxiliary axis B-B is spaced from the main axis A-A, the pistons I6 will reciprocate in their cylinders I5 as the main and auxiliary rotors rotate in the direction of the arrow in Fig. 4 ofthe drawing soa's to displace fluid from the inlet `port I2 Vtothe outlet port I3."In other words,ji.f the auxiliary rotor 'I1 is shifted relative to the main rotor I4 in the direction shownin Fig. 4 ofthe drawing, rotation of the main and auxiliary rotors in the'direction of the arrow B5 will result in inward movement of the pistons I6 during the interval that their cylinders are in communication with the inlet port I2 and will result` in outward movement of the pistons during the interval that their cylinders are in communicationwith the outlet port I3. Thus, each pis`I ton I6 draws av charge of fluid intof its cylinder from the inlet port I2 during the interval that its cylinder is in communication with the inlet port', and4 discharges the charge of fluid intothe outlet port I3 during the interval that its cylinfl der is in communication with theoutlet port.

It will be apparent that the stroke ofy the pistons IB, and, consequently, the displacement of the pump, are dependent on the distance that the auxiliary axis B-B is shifted from the main axis A- -A. In other words, the displacement of the pumpV is zero when the auxiliary axis B-B coincides with the main axis A-A, and is a' V1?--B by means of the cam means I8.

As will be discussed in more detail hereinafter, the camrmeans IB is adapted to move the auxiliary axis B-B in a plane, which is indicatedA by the broken line C-C, so as to maintain the proper relation between the inlet and outlet portsA I2 and lI3 and the positions f the pistoISl ldisposed between the two eccentrics.

JIG in their cylinders I5. The pistons .attain their top and bottom dead center positions with frespect tothe main rotor I4v as they traverse the .plane C-C and this plane is so oriented that `the-pistons attain their top and bottom dead `center positions during the intervals that their cylinders move from positions wherein they communicate with one of the ports I2 or I3 to positions `wherein they communicate with the other of these ports. Preferably, the ports I2 and I3 lie on opposite sides of and equidistant from the plane C-C.

Considering the cam means H9 in more detail, it comprises inner and'outer annular eccentrics l1Ian d l12, the inner eccentric being mounted on the bearing 62 which carries the auxiliary shaft 5,6 and the outer .eccentric ,being mounted on the inner. The outer eccentric 12 is journalled `both the eccentrics 1I and 'I2 from the positions shownin Fig. 1 of the drawing will resultl in lateral shifting of the auxiliary rotor I1 with respect to the main rotor I 4. However, as indicated previously, it is necessary 'to shift the-auxiliary rotor I1 in a predetermined plane,

Vsuch as the plane C-C, in order to maintain-the proper relation between the inletand outlet ports I2 and I3 and the positions of the positions I6, and this is accomplished by rotating :the two eccentrics in synchronism 'between the positions yshown in Fig. 1 of the drawing, wherein the eccentrics are in opposition, and' positions (not shown) wherein the eccentrics are in apposition. The eccentrics 1I and 12 may be said to be in opposition when the lobes thereof, i. e., the positions thereof of greatest radial thickness, are opposite each other, and may be said to be in apposition when'the lobes thereof are in registry. As will be apparent, when the eccentrics 1I and 12 are in opposition, the auxiliary axis B-B coincides with th-e main axis A-A, and when the eccentrics are rotatedftoward the positions wherein they are in apposition, the auxiliary rotor I1 is shifted laterally with respect to the main rotor to space the auxiliary axis from the main axis. In other words, 'when the eccentrics 1I and 12 are in opposition, the displacement of the pump is equal to zero, and when the eccentrics are in apposition, the displacement of the pump is a maximum. As will be apparent, if the eccentrics are rotated from opposition into apposition in synchronism, i. e., at the same angular speed, shifting of the auxiliary motor I1 with respect to the main rotor vIl will take place in the plane C-C as hereinbefore indicated.

Considering the actuating means I9 for rotating the'eccentrics 1I and 12, it comprises a lever 'I8 Iwhich is pivotally connected to the housing I0 at 19, and comprises a lever which is pivotally connected to the housing at 8|, the levers 18 and 80 being pivotally interconnected intermediate their respective ends by a pin `92 which is movable in a slot 83. 'Ihe lever 18 is connected to the eccentric 12 by a, link '85, the latt-er being pivotally connected to the lever 18 at 96 Iand being pivotally connected to the eccentrics 12 at 81. Similarly, the lever 80 is connected to the eccentric 1I by a link 88, the latter being titled by the numerals 81 and 90.

pivotally connected tothe lever 8D at 89 Vand being'7 pivotally lconnected-to the eccentric 1I at su; f Y Y v.As willbe apparent, counterclockwise rotation of the lever.18, vas viewed in Fig. 1 of the drawing, will result in counterclockwise rotation of vthe eccentric 12, and Iwill result in clockwise rotation ofthe lever 80. clockwise rotation of the latter resulting in clockwiseI rotation of the eccentric 1I.v Thus, rotation of the lever 18 about its pivot 19 results in rotation of the eccentric Y'il and 12 in opposite directions. .betweenthe various components of the actuating The relation means I9 is-such that the eccentric 1I and 'I2 are rotated in oppositedirections in synchronism so as to shift `the auxiliary rotor I1 in the plane C Cas hereinbefore:.discussed. The positions of the pivots 81 and 9U when the eccentrics 1I and I2 are in apposition are 4shown in phantom in Fig. `l of the drawing Iand are respectively iden- Although the actuating means I 9 may be oper- -ated in any suitable manner, such as manually, -tov vary the displacement of the pump in the v'which is reciprocable in a cylinder 95. One end of the piston -93 vis exposed to the iluid pressure f obtaining in the outlet port I3 by connecting the 'corresponding end of the cylinder 95 to the outlet port in any suitable manner, as by a tube 96.

`Seated against the opposite end of the piston 93 is a spring '91 which is retained in the cylinder 95 by a plug 98.' Y

It will be apparent that, with the foregoing construction, if the outlet pressure rises above a predetermined value for any reason, the piston will move downwardly, as viewed in Fig. l of the drawing, to operate the actuating means I9 in a manner to rotate the eccentrics 1I and 12 toward positions wherein they are in opposition so as to decrease the displacement of the pump to compensate for the increased outlet pressure. Conversely, if the outlet pressure decreases below a predetermined value. the piston 93 will move upwardly to rotate the eccentrics 1I and 12 toward positions wherein they are in apposition so as to increase the displacement of the pump to compensate for the reduced outlet pressure. As will be apparent, such variations in outlet pressure may arise from variations in the load on the pump.

It will thus be apparent that my invention provides a variable displacement pump which,

'by utilizing the pressure responsive means 20,

'and 'an outlet prt; rotor in said housing and auxiliary axis is spaced from said main axis;

means for pivotally connecting said pistons to said shaft means; and means for shifting said shaft means between said operative and inoperative positions, the shifting means including cam means operatively connected to said shaft means,

a control cylinder carried by said housing, -a control piston reciprocable in said control cylinder. passage means connecting said outlet port to one end of said control cylinder so'that pressure variations in said outlet port result in movement of Said control piston in said control cylinder, and means connecting said control piston to said cam means.

2. In a device of the character described, the

combination of: a housing having an inlet port and an outlet port; a rotor in said housing and rotatable about a main axis, said rotor having a plurality of substantially radial "cylinders means for connecting said cylinders' to said inlet and outlet ports in sequence as said rotor rotates; a plurality of pistons respectively reciprocable in said cylinders; shaft means providing an auxiliary axis substantially parallel to said main axis and shiftable laterally relative to said rotor in a, plane between an inoperative position wherein said auxiliary axis substantially coincides with said main axis and an operative .position '.wherein said auxiliary axis spaced fromsaidxmain axis: means for pivotally connecting said pistons=to1sad shaft means; an inner annular-eccentric rotatable on 'said shaft means; an'outer annular eccentric rotatable on 'said inner eccentric; and actuating means for rotating said eccentrics'in synchronis'm-to shift said shaft means in said-plane between said`operative and inoperative positions, including a rst lever pivotally connected to said housing,

including a secondl lever pivotallyfconnectedto said housing, including means for pvotally connecting said rst lever to said second lever, including means for vpivotally'connecting said first lever to one of said "annularv eccentrics, including means for pivotally connecting said second lever to the other of said annular eccentrics, and including means for rotating'said first lever about its pivotal connection to said housing. i

'3. A Adevice as set forth in claim 2 wherein the means last defined includes means exposed Yto `and responsive to pressure variations in said Q outlet port.'

1 TONY M. MOULDEN.

REFERENCES CITED i v The following references areof record Iin the le of this patent:

UNITED STATES PATENTS y 1,658,705 f C'aprOni Feb. 7, 1928 1,721,225 Levering July 16, 1929 1,757,483 Hele Shaw et a1 May 6,' 1930 A1,939,293 Valentine Oct. 10, 1933 2,115,121 Phillips A. Apr. 26, 1938 2,292,181 -Tucker f Aug. 4,A 1942 2,349,773-1Y Thompson May 23, 1944,

2,393,128 Temple Jan. 15, 1946 

